TYPE. UNITED STATES. Louisiana. [St. Martin parish] St Martinsville, 15.I.1894, A.B. Langlois 738 (US, holotype)
Life form. Lichenized fungus.
Description. [Modified from Aptroot et al. (2014)] Thallus crustose, ecorticate, grayish green to whitish gray, mostly thick, at least minutely rimose or wrinkled; prothallus narrow, black. Vegetative diaspores absent. Photobiont trentepohlioid alga. Ascomata superficial, round, 0.2-0.4 mm diam.; disk grayish to black, flat, epruinose; margin pronounced level with disk, whitish, ~0.1 mm wide. Exciple hyaline, with globose lumina up to 12.5 μm diam. with clusters of hyaline crystals and photobiont cells. Hypothecium black, 35-55 μm thick, often with large hyaline crystals, extending as a thin – thick (to ~50 μm) parathecium between hymenium and exciple. Epihymenium brown, with tiny brownish crystals. Hymenium yellowish, clear; paraphyses 1.5-2.0 μm thick. Asci clavate, 40-50 x 11-14 μm, 8-spored; ascospores hyaline, clavate, 3-septate, 15-18 x 4-6 μm, constricted at septa, ends ± rounded. Conidiomata not seen.
Chemistry. Spot tests negative; no substances detected by TLC.
Substrate and habitat. Corticolous on smooth-barked trees in coastal forests.
Distribution. Neotropical; in North Carolina found in the Coastal Plain ecoregion.
Literature
Aptroot, A., A.A. Menezes, A.B. Xavier-Leite, V.M. dos Santos, M.M.E. Alves & M.E. da S. Cáceres (2014). Revision of the corticolous Mazosia species, with a key to Mazosia species with 3-septate ascospores. The Lichenologist46(4): 563–572.
Eckfeldt, J.W. (1894) Lichens new to North America. Bulletin of the Torrey Botanical Club.21(9): 393-396 (original description as Thelotrema carneum).